Automated test equipment (ATE) can be any testing assembly that performs a test on a semiconductor wafer or die, an integrated circuit (IC), a circuit board, or a packaged device such as a solid-state drive. ATE assemblies may be used to execute automated tests that quickly perform measurements and generate test results that can then be analyzed. An ATE assembly may be anything from a computer system coupled to a meter, to a complicated automated test assembly that may include a custom, dedicated computer control system and many different test instruments that are capable of automatically testing electronics parts and/or semiconductor wafer testing, such as system-on-chip (SOC) testing or integrated circuit testing. ATE systems both reduce the amount of time spent on testing devices to ensure that the device functions as designed and serve as a diagnostic tool to determine the presence of faulty components within a given device before it reaches the consumer.
When a typical ATE system tests a device (commonly referred to as a device under test or DUT), the ATE system applies stimuli (e.g. electrical signals) to the device and checks responses (e.g., currents and voltages) of the device. Typically, the end result of a test is either “pass” if the device successfully provides certain expected responses within pre-established tolerances, or “fail” if the device does not provide the expected responses within the pre-established tolerances. More sophisticated ATE systems are capable of evaluating a failed device to potentially determine one or more causes of the failure.
It is common for an ATE system to include a computer that directs the operation of the ATE system. Typically, the computer runs one or more specialized software programs to provide (i) a test development environment and (ii) a device testing environment. In the test development environment, a user typically creates a test program, e.g., a software-based construct of one or more files that controls various portions of the ATE system. In the device testing environment, the user typically provides the ATE system with one or more devices for testing, and directs the ATE system to test each device in accordance with the test program. The user can test additional devices by simply providing the additional devices to the ATE system, and directing the ATE system to test the additional devices in accordance with the test program. Accordingly, the ATE system enables the user to test many devices in a consistent and automated manner based on the test program.
In a typical prior art testing environment, the DUTs are placed into a controlled environmental chamber or “oven.” The DUTs are connected to slices of a test head. Several DUTs can be connected to a single slice and a single testing chamber may contain several slices. The slices contain the test circuitry which performs tests on the DUTs in accordance with a test plan. When in the oven, the DUTs are not user accessible as to not disturb the controlled environment of the chamber. The plurality of slices generally operate in lock step executing the same test plan on the plurality of DUTs. Further, the test head is typically controlled by a single controller computer system that is directly connected to the test head and, in this fashion, controls all of the slices of the test head. The controller computer is typically operated by a single user executing a single test plan on the DUTs.
A problem of this testing environment is that it is often the case that there are not enough DUTs to completely fill the slices of a given test head during each test. The vacant slices during the test, under such a condition, are therefore wasted in that they are not performing any useful work. These vacancies can reduce overall testing throughput because very expensive electronics sit idle. These idle slices cannot be put to different uses because: 1) the inside of the chamber is not accessible during testing; 2) the control computer supports only one user at any time; and 3) the slices (all of them) operate on only one test plan at a time typically devoted to only one type of DUT.
The test chambers are also bulky and expensive. Another drawback of the conventional testing environment is that a typical customer that wants to share the test chamber between several different user groups, e.g., manufacturing, engineering, etc. concurrently in order to fully utilize the testing chamber is unable to do so. Because the test slices, in typical testing environments, can only operate on a single test plan at a time and support only single user experiences, customers are unable to fully utilize a test chamber at any given time and are, therefore, forced to either purchase additional equipment or sacrifice efficiency. In short, conventional test chambers are very inflexible.